Spill port control for free-piston units



ma 11, 1948. A. ,KALITINSKY SPILL PORT CONTROL FOR FHEE-PISTON UNITS Filed Aug. 23, 1944 2 Sheets-Shq'et 1 mv NToR May 11, 1948. A. KALITINSKY 'SPILL PORT CONTROL FOR FREE-PISTON UNITS Filed Aug. 23, 1944 2 Sheets-Sheet 2 INVENTOR Patented May 11, 1948 SPILL PORT CONTROL FOR FREE-PISTON UNITS Andrew Kalitinsky, Eaglevllle, Conn, asslgnor to United Aircraft Corporation, East Hartiord, Conn., a corporation of Delaware Application August 23, 1944, Serial No. 550,884 2 Claims. (o1. 230-56) 1 This invention relates to a control for the spill ports of a free-piston engine-and-compressor unit. I

The copending application of Poole, Serial No.

531,308, filed April 15, 1944, shows a band 'surrounding the compressor cylinder and movable axially to open or close the spill ports in adjusting the efiective displacement volume of the compressor. A feature of this invention is a band extending around the compressor cylinder and adapted to open or close the ports by angular or circumferential movement.

Another feature is an arrangement by which each row of ports may be opened or closed independently of each other row, so that the several rows may be adjusted in any desired sequence.

A feature of the invention is a separate actuating device for each band so that each band may be operated entirely independently of the position of any of the other bands.

Another feature is a split ring, the ends of which are held together by a spring to permit relative expansion between ring and cylinder.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a sectional view through the freepiston unit.

Fig. 2 is a sectional view on line 2-2 of Fig. 1,

the band actuating means being shown diagrammatically.

The unit shown includes an engine cylinder having reciprocating pistons l2 and it to which compressor pistons l5 and It in cylinders and 22 are integrally connected. Sleeves 24 and 26 attached to the compressor pistons complete the reciprocating piston assemblies. The sleeves in combination with stationary pistons 28 and 30 form air spring cylinders.

Thepiston assemblies are moved apart by the burning of fuel injected into engine cylinder l0 through one or more nozzles 32. Air compressed in the air spring cylinders on the power stroke returns the piston assemblies. The assemblies are always maintained at equal distances from the center of the engine cylinder by a linkage, not shown.

Intake manifold 42, which extends around the compressor and engine cylinders, conducts air to intake valves M in the heads of the compressor cylinders, through which air alternately enters opposite ends of. the cylinders. The compressed air leaves the cylinders through discharge valves 46, also at opposite ends of the compressor cylinders and passes into a central scavenge chamber 48 and end chambers 50 and 52. These chambers may be interconnected by a scavenge manifold, not shown.

Compressed gas irom the scavenge chambers enters engine ports" 54 and 58 which are uncovered by pistons 12 and H at the-end of the power stroke, thereby permitting air to be blown through the engine cylinder. Gas and air in the engine cylinders is discharged through exhaust ports 58 into exhaust manifold 60.

Each compressor cylinder has one or more axially spaced rows of spill ports 62 to permit discharge of air without compression from the cylinder. Each row of ports may be individually controlled by a band M, Fig. 2, extending around the cylinder between projecting ribs 56 extending from the cylinder and having spaced openings 68 for alignment with the spill ports. The ends of the band may have projecting lugs It connected by a spring E2 to hold the band tightly on the cylinder. The band may be moved circumferentially for. opening or closing the ports by means of a hydraulic motor including a cylinder it and a piston 16 having its projecting rod 18 connected to one of the lugs 10. The piston is located to exert a pressure on the lug in a direction substantially tangential to the compressor cylinder.

Fluid may be admitted to either end of cylinder M selectively for moving the associated band. The fluid may be controlled by a master control, as shown in the copending application of Kalitinsky, Serial No. 550,886, filed August 23, 1944, which adjusts the pressure of a control fluid as a function of the spacing of the actual end-of the piston stroke from its extreme end position, the pressure increasing as the stroke shortens.

The control fluid may operate a servomotor by which fluid under pressure is admitted to the cylinder it.

Each row of ports is individually controlled, and may be successively opened or closed, in compensating for changes in the density of the air or gas being compressed.

Intake manifold 42 includes a housing 80 which extends around the compressor cylinder, and end caps 82 and 84 on the housing, forming passages to the intake valves at the outer ends of the compressors. The spill ports 82 open into and are covered by the housing.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other by the following claims. g

Iclaim:

1. A tree-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected for movement as a unit, said compressor cylinder having a number of axially spaced circumferential rows of ports, and a bandior each row of ports, each band extending circumferentially around the compressor cylinder and engaging the outer surface thereof throughout the length of the band, each or said bands having ports therein corresponding in spacing to the ports in the compressor cylinder, and being circumferentially slideable on the compressor cylinder to align its ports with those in the compressor cylinder for the purpose of adjusting the effective volume of the compressor cylinder and means for moving the band circumferentially to open or close the ports for adjusting the efiective volume of the compressor cylinder.

2. A free-piston unit including an engine cylinder and piston, a. compressor cylinder and piston, said pistons being interconnected for movement as a unit, said compressor cylinder having a number of axially spaced circumferential rows of ports, and a discontinuous band for each row of ports extending clrcumferentially around the compressor cylinder, each of said bands having ports therein corresponding in spacing to the ports in the compressor cylinder and each band engaging the outer surface of the compressor cylinder throughout the length of the 4 band, with the ends of the band spaced apart. a spring interconnecting the ends of each band to hold the band in engagement with the compressor cylinder wall, and means for circumferentially sliding each band individually on the compressor cylinder for closing the ports to change the effective volume of the compressor cylinder.

ANDREW KALITINSKY.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 877,492 Doelling Jan. 28, 1908 1,481,358 Dwyer Jan. 22, 2.924. 1,579,782 Riesner Apr, 6, 1926 2,027,877 Pescara Jan. 14, 1936 2,038,442 Pateres-Pescara Apr. 21, 1938 2,064,976 Janlcke Dec. 22, 1936 2,086,228 Janicke July 6, 1937 2,090,709 Steiner Aug. 24, 1937 2,102,121 Janicke Dec. 14, 1937 2,108,890 Janicke Feb. 22, 1936 FOREIGN PATENTS Number Country Date 163,337 Germany 1903 237,170 Germany 1910' 317,872 France 1902 

